package tcp;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


public class TcpEchoServer {
    private ServerSocket serverSocket = null;

    public TcpEchoServer(int port) throws IOException {
        serverSocket = new ServerSocket(port);
    }

    public void start() throws IOException {
        System.out.println("服务器启动!");
        ExecutorService pool = Executors.newCachedThreadPool();
        while(true) {
            Socket clientSocket = serverSocket.accept();
            pool.submit(new Runnable() {
                @Override
                public void run() {
                    processConnection(clientSocket);
                }
            });
        }
    }

    private void processConnection(Socket clientSocket) {
        System.out.printf("[%s:%d] 客户端上线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
        try(InputStream inputStream = clientSocket.getInputStream()) {
            Scanner scanner = new Scanner(inputStream);
            while(true) {
                if(!scanner.hasNext()) {
                    System.out.printf("[%s:%d] 客户端下线!\n",clientSocket.getInetAddress(),clientSocket.getPort());
                    break;
                }
                //1.读取请求并解析
                String request = scanner.next();
                //2.根据请求计算响应
                String response = process(request);
                //3.把响应返回给客户端
                PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
                writer.println(response);
                writer.flush();

                System.out.printf("[%s:%d] res: %s resp:%s\n",clientSocket.getInetAddress(),clientSocket.getPort(),
                        request,response);
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }finally {
            try {
                clientSocket.close();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private String process(String request) {
        return request;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090);
        server.start();
    }
}
